1. Field of the Invention
This invention relates to a hermetic enclosure assembly, having utility for preservational storage and/or display of objects susceptible to degradation by exposure conditions such as ultraviolet radiation, visible light, oxygen, humidity, microbial, fungal, and insect species, internal acidity and external acidic gases (internal acidity being intended here to mean the inherent acidity of the object itself, particularly where the object is of cellulosic composition), and the like, as well as to a method of preservationally and protectively enclosing an object for storage and/or display, wherein the object is of such degradation-susceptible type. This invention is particularly suitable for the storage and/or display of art objects, especially those made of paper, as well as historical documents of various types.
2. Description of the Related Art
Works of art, historical artifacts, and craft items, particularly those made of paper or other cellulosic materials, are susceptible to degradation and destruction by a variety of environmental pests and exposure conditions.
Ultraviolet radiation acts photochemically on polymeric materials and organic materials to degrade them, causing embrittlement of paper and cellulosic web materials, weakening of fabrics, and the bleaching of colors. Visible light energy, particularly in the range of from 400 to 500 nanometers, in the presence of and in interaction with oxygen, initiates photo-oxidation in cellulosic and other materials of construction which leads to their degradation and eventual destruction, in a cumulative fashion, with each instance or continuation of such exposure conditions adding to and promoting the cumulative degradation of the object. Humidity, apart from promoting curling and involutions in paper and other cellulosic materials, can contribute to the occurrence and propagation of mold, slime, and fungi, which may in turn disfigure cellulosic materials and disintegrate them. Paper and other cellulosic materials also are susceptible to attack by microbial species such as bacteria, and by insects that ingest paper. Further, atmospheric pollution can expose cellulosic objects to acidic contaminants which can progressively embrittle and disintegrate the cellulosic objects. In fact, many papers and documents of a valuable character are particularly susceptible to acidic decay as a consequence of paper manufacturing techniques which have been widespread since the middle of the last century, producing papers with internal (inherent) acidity.
Various attempts have been made in the art to develop a hermetically sealed device to frame art or to contain or encapsulate other kinds of valuable objects, as described, for example, in U.S. Pat. Nos. 3,292,339; 4,183,160; and 4,646,914. The deficiencies of the devices described in the first two identified patents are addressed in the third-mentioned patent, issued Mar. 3, 1987 to Jerome Gipson.
The Gipson patent describes an enclosure and mount for display of objects, e.g., works of art. The disclosed enclosure comprises a front plastic covering, mat board, mounting board, plastic foam backing having a desiccant disc therein and a final outside backing. The perimeter of this frame assembly is sealed by pressure-activated film tape after displacing air from the enclosure with inert gas. A moisture indicator is disposed within the enclosure for viewing through a window thereof.
The enclosure assembly described in the Gipson patent suffers the following disadvantages and deficiencies, in use:
1. The Gipson enclosure is assembled in such manner that even as the sealing tape is being applied to form the hermetic seal, the interior volume of the enclosure is being flushed by infusion of an inert gas. This represents a crude and awkward way of attempting to purge the interior volume of air, and provides no reliability as to the desired absence of oxygen from the purged interior volume. A final flushing of the interior volume of the enclosure, by puncturing the tape with a needle, with the tape being sealed again afterward, is not adequate to ensure the desired absence of oxygen in the interior volume. The moisture indicator arrangement of the Gipson enclosure is not adequate for sensing the presence of oxygen which when present creates the danger of interaction with light to cumulatively break down cellulosic fibers. Further, the final flushing of the Gipson assembly causes the enclosure to swell, and the surplus gas trapped within the enclosure is then forced out through the puncture hole by compressing the entire assembly between two sheets of plywood or plastic. This procedure creates a substantial risk of harm to any object mounted in the enclosure that is in any way fragile. The greater the pressure involved to achieve expulsion of surplus gas from the enclosure, the greater the risk of harm to the enclosed object. By way of example, brittle documents, pastels whose surface-lying pigments are intolerant of fixatives, collages of fragile papers with highly textured but tenuous surfaces, paintings the surfaces of which are crackled, and charcoal drawings that conservationally must avoid fixatives, to give but a few examples, could not be submitted to the conditions required by the Gipson patent, without engendering the risk of damage to or destruction of the enclosed object.
2. The Gipson assembly is primarily directed to control of humidity and prevention of atmospheric moisture from entering the interior. A desiccant, provided as an indicant of moisture, will undergo color change when the humidity enters the interior of the enclosure. It will also undergo color change when, in the normal course of affairs, humidity from the mounted object will be drawn via evaporation into the enclosure. Two undesirable occurrences would result: (i) a false positive indication might occur concerning the moisture contamination of the enclosure, requiring that the assembly be discarded or rebuilt, or (ii) the normal humidity associated with the object could in time become extracted from it, to the detriment of its structural integrity. This is particularly true of objects constructed of cellulosic materials which require some moisture content to retain structural integrity and properties.
3. The flexible sealing tape of the Gipson assembly will in time dry out and lose its efficacy as an hermetic seal.
4. The flexible sealing tape of the Gipson assembly is non-immune to penetration and damage by insects.
5. The back of the Gipson assembly is formed by a plate of foam core material containing a cavity for the desiccant. Such foam core material, however, readily loses its shape, and the back plate additionally is not itself isolated from humidity and the effects of atmospheric moisture. As a result, changes in the back plate moisture content and overall shape will cause stressing of the hermetic seal both at the periphery and at the seal associated with the cavity containing the desiccant. Such change in the shape of the back plate may also affect the mounting board, altering its shape from its original flatness to a curved or involuted shape, which can in turn place stress on the object mounted on the mounting board. These effects may be further compounded by the fact that the window plate, made of plastic or acrylic, will produce an electrostatic field that will exert an electrostatic force on the mounted object. Accordingly, a valuable art work or object mounted in the Gipson assembly potentially could be impacted by opposing forces involving the stress and strain behavior which could damage the mounted object and/or enclosure components over time, particularly if the objects are fragile or have tenuous surfaces.
6. Foam core is a flammable material of construction, and thus creates some risk of danger and harm to valuable art or documents mounted in such enclosure.
7. The Gipson frame does not provide UV filtering.
Accordingly, it would be a substantial advantage in the art of preservational storage and/or display of objects susceptible to degradation by exposure conditions such as ultraviolet radiation, visible light, oxygen, humidity, microbial, fungal, and insect species, internal acidity and external acidic gases, and the like, to provide a hermetic enclosure assembly overcoming the aforementioned deficiencies of the prior art.
It therefore is an object of the present invention to provide such a hermetic enclosure assembly, which is simple in construction, and readily assembled (and disassembled, if need be), which restricts the ingress of UV and other actinic radiation to the mounted object in the enclosure, which prevents the interaction of visible light and oxygen cumulatively to destroy polymeric materials, particularly the fibers of cellulosic objects, which effectively deacidifies any acidic mounted objects and establishes and maintains neutral pH conditions in the enclosure, and which does not dehydrate mounted objects to a point of embrittlement or decay, in the case of cellulosic objects such as paper.
It is another object of the invention to provide a method of preservationally and protectively enclosing an object for storage and/or display, which achieves the advantages and benefits stated in the preceding paragraph.
Other objects and advantages of the invention will be more fully apparent from the ensuing disclosure and appended claims.